The proposed research will investigate oral mucosal immunization as a potential route for delivery of human immunodeficiency virus (HIV) vaccines. Like most other sexually transmitted diseases (STDs), HIV's primary site of infection is at mucosal surfaces, and like most other STDs, there is no vaccine for HIV. The proposed experiments will explore the possible use of the oral mucosal route for immunization against HIV/STDs through induction of immunity at distal sites mediated via the common mucosal immune system. We will characterize innate, adaptive cellular, and humoral responses in the periphery and in mucosal (oral, nasal, pulmonary, rectal, and vaginal) sites to vaccines given at 2 oral mucosal sites (submucosal immunization in the buccal fossa and over the lingual tonsil) and compare them to responses to the same vaccines given intramuscularly (IM) or intradermally (ID). The first set of experiments, in rhesus macaques, will use an SIV version of one of the leading HIV vaccine regimens: DNA prime/replication-incompetent Ad5 vaccine boost. We will extend our observations to humans using a licensed inactivated influenza vaccine (Fluzone.) as a test antigen. Adaptive responses will be measured in the blood and at mucosal sites;antigen-specific T cells will be measured using ELISpot and intracellular cytokine staining and antibody will be measured by ELISA. Aim 1 will test whether submucosal immunization over the lingual tonsil produces robust peripheral B- and T-cell responses in both nonhuman primates (NHPs) and humans. This aim will address whether peripheral responses after lingual tonsil immunization approximate those induced by IM or ID immunization and are greater than those seen after submucosal immunization in the buccal fossa. Possible mechanisms underlying differences in adaptive responses elicited by different routes will be investigated via studies of innate immune responses (systemic dendritic cell phenotype and function, and serum cytokine/chemokine profiles). Aim 2 will address whether lingual tonsil immunization induces mucosal cellular and humoral responses at measurably higher levels than buccal or IM/ID immunization. This aim will determine whether T-cell responses elicited by the lingual tonsil route show higher functionality and avidity, and if this route elicits responses in distal mucosal sites (rectum and cervix/vagina). Project Narrative: These experiments will provide data on whether vaccination of the oral mucosa can provide protection against sexually transmitted organisms, through induction of immunity at distal sites (such as the vaginal and rectum) mediated by the common mucosal immune system. It will also investigate the usefulness of this route of immunization for protection against respiratory pathogens, such as influenza, when immunity in the nose and lungs is desired.